Attics Are Not a reception friendly environment and Never Will be a reception friendly environment.
That said , the Digital Tv transmissions are strong at your location.
Yes start with a Winegard HD7000R antenna in the attic aimed at about 305 degree magnetic compass direction.
Here is how to aim antennas ,
http://www.kyes.com/antenna/pointing/pointing.html.
If there are reception issues that are not resolvable buy adjusting the aim or location of the antenna in the attic then move the HD7000R antenna to above the roof.
Install the HD7000R antenna above the roof in such a manner that the roof is not blocking reception in the directions of reception.
At your location that is , west , north west , north , east , south.
Here are some above the roof antenna mounts ,
http://www.ronard.com/909911.html ,
http://www.ronard.com/34424560.html if using a eave mount use the #4560 ,
http://www.ronard.com/ychim.html ,
http://www.ronard.com.
Buy the ronard antenna mounts at solidsignal by typing the word ronard in the solidsignal search box.
A preamplifier is not required.
For 1 Tv connected use no splitter.
For 2 Tv's connected use a common simple 2 way splitter.
For 3 Tv's connected use a common simple 3 way splitter.
No requirement to use , gold plated digital super whiz bang splitter that cost $50.00.
Here are some places to buy antennas and etc. ,
http://www.solidsignal.com ,
http://www.amazon.com ,
http://www.winegarddirect.com.
As always , trees and tree leaves do a real fine job of reducing or blocking Tv reception and so do buildings and other obstructions including your own house.
It is best to install the HD7000R antenna at a location that has the least amount to no amount of obstructions of any type or kind in the directions of reception including your own house.
The Tv/s Must Channel Scan for the Broadcast Tv Channels , some times named the 'Air Channels' or 'Antenna Channels' in the the Tv setup menu because the Tv transmissions travel through the air from the transmitting antenna to the receiving antenna.
DO NOT channel scan for cable tv channels.